I have two of those coolers, and to be honest, they don't always spin. If you have a well designed case with good cooling and cleaning wiring, it might not always spin. For example, on my new Sandy Bridge system, the fans spins when I boot up, and but comes to a stop soon after, and my proc temps are always good. Take the side off your case and watch the fan. Then load up a game or something intensive, and see if it kicks on. If so, you're fine.